Description

Several decades of tree improvement operations have drastically increased loblolly pine plantation productivity in the southern U.S. (McKeand et al., 2003). This work has lead to the availability of a number of highly productive open-pollinated and full-sib families (McKeand et al., 2006). In addition, vegetative propagation (somatic embryogenesis) has also made it possible to clonally multiply elite genotypes (Bettinger et al., 2009). Open-pollinated, full-sib, and clonal trees contain varying amounts of inherent genetic variation which allows land managers to balance the gains and risks of deploying less genetically diverse, yet potentially more productive genotypes (Bridgwater et al., 2005). In many forest plantation species, deployment of clones has been suggested to result in more uniform plantation growth and development (DeBell and Harrington, 1997, Bettinger et al., 2009), and greater stand uniformity may lead to greater resource-use efficiency and enhanced productivity (Binkley et al., 2010, Ryan et al., 2010a).